2 page-layout-problem.cc -- space systems nicely on a page. If systems can
3 be stretched, do that too.
5 source file of the GNU LilyPond music typesetter
7 (c) 2009 Joe Neeman <joeneeman@gmail.com>
10 #include "page-layout-problem.hh"
12 #include "align-interface.hh"
13 #include "axis-group-interface.hh"
14 #include "hara-kiri-group-spanner.hh"
15 #include "international.hh"
17 #include "output-def.hh"
18 #include "paper-book.hh"
19 #include "paper-column.hh"
20 #include "pointer-group-interface.hh"
22 #include "skyline-pair.hh"
25 Page_layout_problem::Page_layout_problem (Paper_book *pb, SCM page_scm, SCM systems)
26 : bottom_skyline_ (DOWN)
28 Prob *page = unsmob_prob (page_scm);
37 Stencil *head = unsmob_stencil (page->get_property ("head-stencil"));
38 Stencil *foot = unsmob_stencil (page->get_property ("foot-stencil"));
40 header_height_ = head ? head->extent (Y_AXIS).length () : 0;
41 footer_height_ = foot ? foot->extent (Y_AXIS).length () : 0;
42 page_height_ = robust_scm2double (page->get_property ("paper-height"), 100);
45 // Initially, bottom_skyline_ represents the top of the page. Make
46 // it solid, so that the top of the first system will be forced
47 // below the top of the printable area.
48 bottom_skyline_.set_minimum_height (-header_height_);
50 SCM between_system_spacing = SCM_EOL;
51 SCM between_scores_system_spacing = SCM_EOL;
52 SCM after_title_spacing = SCM_EOL;
53 SCM before_title_spacing = SCM_EOL;
54 SCM between_title_spacing = SCM_EOL;
56 // top_system_spacing controls the spring from the top of the printable
57 // area to the first staff. It allows the user to control the offset of
58 // the first staff (as opposed to the top of the first system) from the
59 // top of the page. Similarly for bottom_system_spacing.
60 SCM top_system_spacing = SCM_EOL;
61 SCM bottom_system_spacing = SCM_EOL;
64 Output_def *paper = pb->paper_;
65 between_system_spacing = paper->c_variable ("between-system-spacing");
66 between_scores_system_spacing = paper->c_variable ("between-scores-system-spacing");
67 after_title_spacing = paper->c_variable ("after-title-spacing");
68 before_title_spacing = paper->c_variable ("before-title-spacing");
69 between_title_spacing = paper->c_variable ("between-title-spacing");
70 bottom_system_spacing = paper->c_variable ("bottom-system-spacing");
71 top_system_spacing = paper->c_variable ("top-system-spacing");
72 if (scm_is_pair (systems) && unsmob_prob (scm_car (systems)))
73 top_system_spacing = paper->c_variable ("top-title-spacing");
75 // Note: the page height here does _not_ reserve space for headers and
76 // footers. This is because we want to anchor the top-system-spacing
77 // spring at the _top_ of the header.
78 page_height_ -= robust_scm2double (paper->c_variable ("top-margin"), 0)
79 + robust_scm2double (paper->c_variable ("bottom-margin"), 0);
81 read_spacing_spec (top_system_spacing, &header_padding_, ly_symbol2scm ("padding"));
82 read_spacing_spec (bottom_system_spacing, &footer_padding_, ly_symbol2scm ("padding"));
84 bool last_system_was_title = false;
87 for (SCM s = systems; scm_is_pair (s); s = scm_cdr (s))
89 bool first = (s == systems);
91 if (Grob *g = unsmob_grob (scm_car (s)))
93 System *sys = dynamic_cast<System*> (g);
96 programming_error ("got a grob for vertical spacing that wasn't a System");
100 SCM spec = between_system_spacing;
102 spec = top_system_spacing;
103 else if (last_system_was_title)
104 spec = after_title_spacing;
105 else if (0 == Paper_column::get_rank (sys->get_bound (LEFT)))
106 spec = between_scores_system_spacing;
108 Spring spring (first ? 0 : 1, 0.0);
110 alter_spring_from_spacing_spec (spec, &spring);
111 read_spacing_spec (spec, &padding, ly_symbol2scm ("padding"));
113 append_system (sys, spring, padding);
114 last_system_was_title = false;
116 else if (Prob *p = unsmob_prob (scm_car (s)))
118 SCM spec = first ? top_system_spacing
119 : (last_system_was_title ? between_title_spacing : before_title_spacing);
120 Spring spring (first ? 0 : 1, 0.0);
122 alter_spring_from_spacing_spec (spec, &spring);
123 read_spacing_spec (spec, &padding, ly_symbol2scm ("padding"));
125 append_prob (p, spring, padding);
126 last_system_was_title = true;
129 programming_error ("got a system that was neither a Grob nor a Prob");
132 Spring last_spring (0, 0);
133 Real last_padding = 0;
134 alter_spring_from_spacing_spec (bottom_system_spacing, &last_spring);
135 read_spacing_spec (bottom_system_spacing, &last_padding, ly_symbol2scm ("padding"));
136 last_spring.ensure_min_distance (last_padding - bottom_skyline_.max_height () + footer_height_);
137 springs_.push_back (last_spring);
139 if (elements_.size ())
141 Real bottom_padding = 0;
143 // TODO: junk bottom-space now that we have bottom-system-spacing?
144 // bottom-space has the flexibility that one can do it per-system.
145 // NOTE: bottom-space is misnamed since it is not stretchable space.
146 if (Prob *p = elements_.back ().prob)
147 bottom_padding = robust_scm2double (p->get_property ("bottom-space"), 0);
148 else if (elements_.back ().staves.size ())
150 SCM details = get_details (elements_.back ());
151 bottom_padding = robust_scm2double (ly_assoc_get (ly_symbol2scm ("bottom-space"),
156 page_height_ -= bottom_padding;
161 Page_layout_problem::set_header_height (Real height)
163 header_height_ = height;
167 Page_layout_problem::set_footer_height (Real height)
169 footer_height_ = height;
173 Page_layout_problem::append_system (System *sys, Spring const& spring, Real padding)
175 Grob *align = sys->get_vertical_alignment ();
179 align->set_property ("positioning-done", SCM_BOOL_T);
181 extract_grob_set (align, "elements", all_elts);
182 vector<Grob*> elts = filter_dead_elements (all_elts);
183 vector<Real> minimum_offsets = Align_interface::get_minimum_translations (align, elts, Y_AXIS,
186 Skyline up_skyline (UP);
187 Skyline down_skyline (DOWN);
188 build_system_skyline (elts, minimum_offsets, &up_skyline, &down_skyline);
190 Real minimum_distance = up_skyline.distance (bottom_skyline_) + padding;
192 Spring spring_copy = spring;
193 spring_copy.ensure_min_distance (minimum_distance);
194 springs_.push_back (spring_copy);
196 bottom_skyline_ = down_skyline;
197 elements_.push_back (Element (elts, minimum_offsets));
199 // Add the springs for the VerticalAxisGroups in this system.
201 // If the user has specified the offsets of the individual staves, fix the
202 // springs at the given distances. Otherwise, use stretchable springs.
203 SCM details = get_details (elements_.back ());
204 SCM manual_dists = ly_assoc_get (ly_symbol2scm ("alignment-distances"), details, SCM_EOL);
205 vsize last_spaceable_staff = 0;
206 bool found_spaceable_staff = false;
207 for (vsize i = 0; i < elts.size (); ++i)
209 if (is_spaceable (elts[i]))
211 // We don't add a spring for the first staff, since
212 // we are only adding springs _between_ staves here.
213 if (!found_spaceable_staff)
215 found_spaceable_staff = true;
216 last_spaceable_staff = i;
220 Spring spring (0.5, 0.0);
221 SCM spec = elts[last_spaceable_staff]->get_property ("next-staff-spacing");
222 alter_spring_from_spacing_spec (spec, &spring);
224 springs_.push_back (spring);
225 Real min_distance = (found_spaceable_staff ? minimum_offsets[last_spaceable_staff] : 0) - minimum_offsets[i];
226 springs_.back ().ensure_min_distance (min_distance);
228 if (scm_is_pair (manual_dists))
230 if (scm_is_number (scm_car (manual_dists)))
232 Real dy = scm_to_double (scm_car (manual_dists));
234 springs_.back ().set_distance (dy);
235 springs_.back ().set_min_distance (dy);
236 springs_.back ().set_inverse_stretch_strength (0);
238 manual_dists = scm_cdr (manual_dists);
240 last_spaceable_staff = i;
244 // Corner case: there was only one staff, and it wasn't spaceable.
245 // Mark it spaceable, because we do not allow non-spaceable staves
246 // to be at the top or bottom of a system.
247 if (!found_spaceable_staff && elts.size ())
248 mark_as_spaceable (elts[0]);
252 Page_layout_problem::append_prob (Prob *prob, Spring const& spring, Real padding)
254 Skyline_pair *sky = Skyline_pair::unsmob (prob->get_property ("vertical-skylines"));
255 Real minimum_distance = 0;
258 minimum_distance = (*sky)[UP].distance (bottom_skyline_);
259 bottom_skyline_ = (*sky)[DOWN];
261 else if (Stencil *sten = unsmob_stencil (prob->get_property ("stencil")))
263 Interval iv = sten->extent (Y_AXIS);
264 minimum_distance = iv[UP] - bottom_skyline_.max_height ();
266 bottom_skyline_.clear ();
267 bottom_skyline_.set_minimum_height (iv[DOWN]);
269 minimum_distance += padding;
271 Spring spring_copy = spring;
272 spring_copy.ensure_min_distance (minimum_distance);
273 springs_.push_back (spring_copy);
274 elements_.push_back (Element (prob));
278 Page_layout_problem::solve_rod_spring_problem (bool ragged)
280 Simple_spacer spacer;
282 for (vsize i = 0; i < springs_.size (); ++i)
283 spacer.add_spring (springs_[i]);
285 spacer.solve (page_height_, ragged);
286 solution_ = spacer.spring_positions ();
289 // The solution_ vector stores the position of every live VerticalAxisGroup
290 // and every title. From that information,
291 // 1) within each system, stretch the staves so they land at the right position
292 // 2) find the offset of each system (relative to the printable area of the page).
293 // TODO: this function is getting too long, maybe split it up?
295 Page_layout_problem::find_system_offsets ()
297 SCM system_offsets = SCM_EOL;
298 SCM *tail = &system_offsets;
300 // spring_idx 0 is the top of the page. Interesting values start from 1.
301 vsize spring_idx = 1;
302 vector<Grob*> loose_lines;
303 vector<Real> loose_line_min_distances;
304 Grob *last_spaceable_line = 0;
305 Real last_spaceable_line_translation = 0;
306 for (vsize i = 0; i < elements_.size (); ++i)
308 if (elements_[i].prob)
310 *tail = scm_cons (scm_from_double (solution_[spring_idx]), SCM_EOL);
311 tail = SCM_CDRLOC (*tail);
313 // Lay out any non-spaceable lines between this line and
315 if (loose_lines.size ())
317 Interval loose_extent = loose_lines.back ()->extent (loose_lines.back (), Y_AXIS);
318 Interval prob_extent = unsmob_stencil (elements_[i].prob->get_property ("stencil"))->extent (Y_AXIS);
319 Real min_distance = -loose_extent[DOWN] + prob_extent[UP]; // TODO: include padding/minimum-distance
321 loose_line_min_distances.push_back (min_distance);
322 loose_lines.push_back (0);
324 distribute_loose_lines (loose_lines, loose_line_min_distances,
325 last_spaceable_line_translation, -solution_[spring_idx]);
326 loose_lines.clear ();
327 loose_line_min_distances.clear ();
330 last_spaceable_line = 0;
331 last_spaceable_line_translation = -solution_[spring_idx];
336 // Getting this signs right here is a little tricky. The configuration
337 // we return has zero at the top of the page and positive numbers further
338 // down, as does the solution_ vector. Within a staff, however, positive
340 // TODO: perhaps change the way the page 'configuration variable works so
341 // that it is consistent with the usual up/down sign conventions in
342 // Lilypond. Then this would be less confusing.
344 // These two positions are relative to the page (with positive numbers being
346 Real first_staff_position = solution_[spring_idx];
347 Real first_staff_min_translation = elements_[i].min_offsets.size () ? elements_[i].min_offsets[0] : 0;
348 Real system_position = first_staff_position + first_staff_min_translation;
350 // Position the staves within this system.
351 Real translation = 0;
352 vector<Real> const& min_offsets = elements_[i].min_offsets;
353 bool found_spaceable_staff = false;
354 for (vsize staff_idx = 0; staff_idx < elements_[i].staves.size (); ++staff_idx)
356 Grob *staff = elements_[i].staves[staff_idx];
357 staff->set_property ("system-Y-offset", scm_from_double (-system_position));
359 if (is_spaceable (staff))
361 // this is relative to the system: negative numbers are down.
362 translation = system_position - solution_[spring_idx];
365 // Lay out any non-spaceable lines between this line and
367 if (loose_lines.size ())
369 loose_line_min_distances.push_back (min_offsets[staff_idx-1] - min_offsets[staff_idx]);
370 loose_lines.push_back (staff);
372 distribute_loose_lines (loose_lines, loose_line_min_distances,
373 last_spaceable_line_translation, translation - system_position);
374 loose_lines.clear ();
375 loose_line_min_distances.clear ();
377 last_spaceable_line = staff;
378 // Negative is down but the translation is relative to the whole page.
379 last_spaceable_line_translation = -system_position + translation;
381 staff->translate_axis (translation, Y_AXIS);
382 found_spaceable_staff = true;
386 if (loose_lines.empty ())
387 loose_lines.push_back (last_spaceable_line);
389 loose_lines.push_back (staff);
391 loose_line_min_distances.push_back (min_offsets[staff_idx-1] - min_offsets[staff_idx]);
395 if (last_spaceable_line)
396 min_dist = Axis_group_interface::minimum_distance (last_spaceable_line,
399 else // distance to the top margin
400 min_dist = header_padding_ + header_height_ + staff->extent (staff, Y_AXIS)[UP];
402 loose_line_min_distances.push_back (min_dist);
407 // Corner case: even if a system has no live staves, it still takes up
408 // one spring (a system with one live staff also takes up one spring),
409 // which we need to increment past.
410 if (!found_spaceable_staff)
413 *tail = scm_cons (scm_from_double (system_position), SCM_EOL);
414 tail = SCM_CDRLOC (*tail);
418 if (loose_lines.size ())
420 Grob *last = loose_lines.back ();
421 Interval last_ext = last->extent (last, Y_AXIS);
422 loose_line_min_distances.push_back (-last_ext[DOWN] + footer_height_ + footer_padding_);
423 loose_lines.push_back (0);
425 distribute_loose_lines (loose_lines, loose_line_min_distances,
426 last_spaceable_line_translation, -page_height_);
430 assert (spring_idx == solution_.size () - 1);
431 return system_offsets;
434 // Given two lines that are already spaced (the first and last
435 // elements of loose_lines), distribute some unspaced lines between
438 Page_layout_problem::distribute_loose_lines (vector<Grob*> const &loose_lines,
439 vector<Real> const &min_distances,
440 Real first_translation, Real last_translation)
442 Simple_spacer spacer;
443 for (vsize i = 0; i + 1 < loose_lines.size (); ++i)
445 SCM spec = get_spacing_spec (loose_lines[i], loose_lines[i+1]);
446 Spring spring (1.0, 0.0);
447 alter_spring_from_spacing_spec (spec, &spring);
448 spring.ensure_min_distance (min_distances[i]);
450 if ((spec == SCM_BOOL_F && loose_lines[0] && loose_lines.back ())
452 || !loose_lines[i+1])
454 // Insert a very flexible spring, so it doesn't have much effect.
455 // TODO: set a default distance and a compress strength so that a
456 // lyrics line, for example, will stay closer to the top staff
457 // even in a compressed configuration.
458 spring.set_inverse_stretch_strength (100000);
459 spring.set_inverse_compress_strength (100000);
462 spacer.add_spring (spring);
465 // Remember: offsets are decreasing, since we're going from UP to DOWN!
466 spacer.solve (first_translation - last_translation, false);
468 vector<Real> solution = spacer.spring_positions ();
469 for (vsize i = 1; i + 1 < solution.size (); ++i)
471 Real system_offset = scm_to_double (loose_lines[i]->get_property ("system-Y-offset"));
472 loose_lines[i]->translate_axis (first_translation - solution[i] - system_offset, Y_AXIS);
477 Page_layout_problem::solution (bool ragged)
479 solve_rod_spring_problem (ragged);
480 return find_system_offsets ();
483 // Build upper and lower skylines for a system. We don't yet know the positions
484 // of the staves within the system, so we make the skyline as conservative as
485 // possible. That is, for the upper skyline, we pretend that all of the staves
486 // in the system are packed together close to the top system; for the lower
487 // skyline, we pretend that all of the staves are packed together close to
488 // the bottom system.
490 // The upper skyline is relative to the top staff; the lower skyline is relative to
493 Page_layout_problem::build_system_skyline (vector<Grob*> const& staves,
494 vector<Real> const& minimum_translations,
498 if (minimum_translations.empty ())
501 assert (staves.size () == minimum_translations.size ());
502 Real first_translation = minimum_translations[0];
503 Real last_spaceable_dy = 0;
504 Real first_spaceable_dy = 0;
505 bool found_spaceable_staff = false;
507 for (vsize i = 0; i < staves.size (); ++i)
509 Real dy = minimum_translations[i] - first_translation;
511 Skyline_pair *sky = Skyline_pair::unsmob (g->get_property ("vertical-skylines"));
515 up->merge ((*sky)[UP]);
519 down->merge ((*sky)[DOWN]);
522 if (is_spaceable (staves[i]))
524 if (!found_spaceable_staff)
526 found_spaceable_staff = true;
527 first_spaceable_dy = dy;
529 last_spaceable_dy = dy;
533 // Leave the up skyline at a position relative
534 // to the top spaceable staff.
535 up->raise (-first_spaceable_dy);
537 // Leave the down skyline at a position
538 // relative to the bottom spaceable staff.
539 down->raise (-last_spaceable_dy);
543 Page_layout_problem::prob_extent (Prob *p)
545 Stencil *sten = unsmob_stencil (p->get_property ("stencil"));
546 return sten ? sten->extent (Y_AXIS) : Interval (0, 0);
550 Page_layout_problem::first_staff_extent (Element const& e)
553 return prob_extent (e.prob);
554 else if (e.staves.size ())
555 return e.staves[0]->extent (e.staves[0], Y_AXIS);
557 return Interval (0, 0);
561 Page_layout_problem::last_staff_extent (Element const& e)
564 return prob_extent (e.prob);
565 else if (e.staves.size ())
566 return e.staves.back ()->extent (e.staves.back (), Y_AXIS);
568 return Interval (0, 0);
572 Page_layout_problem::get_details (Element const& elt)
574 if (elt.staves.empty ())
577 return get_details (elt.staves.back ()->get_system ());
581 Page_layout_problem::get_details (Grob *g)
583 Grob *left_bound = dynamic_cast<Spanner*> (g)->get_bound (LEFT);
584 return left_bound->get_property ("line-break-system-details");
588 Page_layout_problem::is_spaceable (Grob *g)
590 return !scm_is_number (g->get_property ("staff-affinity"));
594 Page_layout_problem::mark_as_spaceable (Grob *g)
596 g->set_property ("staff-affinity", SCM_BOOL_F);
600 Page_layout_problem::read_spacing_spec (SCM spec, Real* dest, SCM sym)
602 SCM pair = scm_sloppy_assq (sym, spec);
603 if (scm_is_pair (pair) && scm_is_number (scm_cdr (pair)))
605 *dest = scm_to_double (scm_cdr (pair));
611 // Returns the spacing spec connecting BEFORE to AFTER. A return
612 // value of SCM_BOOL_F means that there should be no spring (in
613 // practice, this means that we use a very flexible spring).
615 Page_layout_problem::get_spacing_spec (Grob *before, Grob *after)
617 if (!before || !after)
620 if (is_spaceable (before))
622 if (is_spaceable (after))
623 return before->get_property ("next-staff-spacing");
626 Direction affinity = to_dir (after->get_property ("staff-affinity"));
627 return (affinity == DOWN) ? SCM_BOOL_F : after->get_property ("inter-staff-spacing");
632 if (is_spaceable (after))
634 Direction affinity = to_dir (before->get_property ("staff-affinity"));
635 return (affinity == UP) ? SCM_BOOL_F : before->get_property ("inter-staff-spacing");
639 Direction before_affinity = to_dir (before->get_property ("staff-affinity"));
640 Direction after_affinity = to_dir (after->get_property ("staff-affinity"));
641 if (after_affinity > before_affinity)
643 warning (_ ("staff-affinities should only decrease"));
644 after_affinity = before_affinity;
646 if (before_affinity != UP)
647 return before->get_property ("inter-loose-line-spacing");
648 else if (after_affinity != DOWN)
649 return before->get_property ("inter-loose-line-spacing");
656 Page_layout_problem::alter_spring_from_spacing_spec (SCM spec, Spring* spring)
661 if (read_spacing_spec (spec, &space, ly_symbol2scm ("space")))
662 spring->set_distance (space);
663 if (read_spacing_spec (spec, &min_dist, ly_symbol2scm ("minimum-distance")))
664 spring->set_min_distance (min_dist);
665 spring->set_default_strength ();
667 if (read_spacing_spec (spec, &stretch, ly_symbol2scm ("stretchability")))
669 spring->set_inverse_stretch_strength (stretch);
670 spring->set_inverse_compress_strength (stretch);
675 Page_layout_problem::filter_dead_elements (vector<Grob*> const& input)
677 vector<Grob*> output;
678 for (vsize i = 0; i < input.size (); ++i)
680 if (Hara_kiri_group_spanner::has_interface (input[i]))
681 Hara_kiri_group_spanner::consider_suicide (input[i]);
683 if (input[i]->is_live ())
684 output.push_back (input[i]);